1. Field of the Invention
This invention relates to a system for the control of insects, especially cockroaches, that includes hydrodynamic baits, that can be flowable or formable, and to a method for controlling insects, especially cockroaches, using the hydrodynamic baits.
2. Description of the Related Art
Cockroaches are primarily tropical insects but some species have become widely disseminated through commercial activities and are now cosmopolitan. The domestic species are omnivorous but are especially attracted to starchy or sweetened matter of various kinds; they also attack food, paper, clothing, books, shoes, bones, and dead insects. They are the orthopterous insects that are involved in the contamination of food. Of the many species of cockroaches, house inhabitors include American (Periplaneta americana), oriental (Blatta orientalis), Australian (P. australasiae), German (Blattella germanica), brownbanded (Supella longipalpa (F.)), smokybrown (P. fuliginosa (Serville)), and Florida woods (Eurycotis floridana (Walker)) cockroaches. They prefer secluded, warm, damp places and at night or on dark days, they sample filth and foods and impart to infested areas an unpleasant odor.
A number of food attractants have been formulated with toxicants and aqueous gel binders to provide toxic paste baits for cockroaches. For example, Doi et al. (Chem. Abst. 107:12915n(1987)) controlled cockroaches with a paste containing boric acid, potato strach, corn strach, rice bran, molasses, water, and dye; Barson (Chem. Abst. 97:87017k(1982)) used a mixture of boric acid plus porridge oats and iodofenphos gel; Peeters (Chem. Abst. 84:131508d (1976)) combined bakery wastes, boric acid, and water. Similarly, the proprietary roach bait station sold under the trademark, "It Works" (Bridgeport, Conn.) is advertised as containing boric acid, an attractant, and a humectant.
One of the key necessities for arthropod survival is moisture. When temperatures increase, the metabolism of cockroaches and other insects increase. Subsequently, they have an increased need for food and will find a bait that is also a good moisture source. Silverman (Australian Document No. AU-B-73766/87) discloses a bait that incorporates water as an attractant to lure cockroaches to a poisoned bait. The bait is a solid, non-particulate, non-flowable, non-repellent, fully edible insecticide-bait composition with a pentadienone hydrazone insecticide compound, a specific food attractant system and a binder. The water attractant can be in a container close to the bait or in a cup-like container built into the feeding station containing the bait. The water can also be formulated into the bait using a water absorbent material such as a water absorbing polymer, especially an electrolyte polymer that does not contain natural polymer such as starch and contains synthetic carboxylate and hydroxyl groups, has a high water-absorption ratio and has excellent water-retaining properties as well as good strength after absorbing water. The particular polymers are a saponified copolymer of vinyl ester (x) and ethylenic unsaturated carboxylic acid or its derivative (y) sold under the name SUMIKAGEL.RTM. S-50 and the polyvinyl alcohol-acrylate graft polymer.
Ong (U.S. Pat. No. 4,812,309) discloses a gel composition for the control of cockroaches that includes a gellant, propyl p-hydroxybenzoate, propylene glycol, fatty acids, an insecticide, high fructose corn syrup, isopropyl alcohol, methyl p-hydroxybenzoate and water where the gellant is a non-ionic surfactant. The composition can be distributed so that it poses little or no hazard to humans or animals that may frequent the infested area.
Brenner et al (U.S. Pat. No. 4,988,510, herein incorporated by reference) disclose a hydrophilic gel bait which is deformable (non-flowable) that includes corn distiller's grains with solubles as an attractant for cockroaches. This bait includes a humectant, insecticide, a gel former, and optionally a preservative. This bait provides both food and a relatively moist environment for cockroaches.
Dried mash from a distillery was reported by Adler (J. Environ. Sci. Hlth., A20:839-844(1985)) to be specifically attractive for the brownbanded cockroach, Supella longipalpa (F.), but it failed to attract American cockroaches, Periplaneta americana (L.). In contrast, Brenner et al (Ann. Entomol. Soc. Am. 81:581-592 (1988); J. Econ. Entomol. 82:159-162(1989)) reported that distiller's dried grains with solubles (DDGS, Agricultural Energy Corp., Franklin, Ky.) was attractive to 15 species of cockroaches including American cockroaches. Furthermore, the DDGS is advantageously unattractive to nontarget mammals, in contrast to other baits such as pieces of fruit, bread, and beer (Jackson et al., Am. J. Trop. Med. Hyg. 4:141-146 (1955); Ohio J. Sci., 61:220-226 (1961); Reierson et al., Pest Control 45:40, 42-44 (1977); Fleet et al., Environ. Entomol. 14:669-673(1985) or dry cat food (Appel et al., Environ. Entomol. 14669-673(1985)) which are attractive to mammals as well as cockroaches.
Bruey (U.S. Pat. No. 5,021,237) discloses a gel insecticide bait that is dispensed from a pressurized container which is made up of a pentadienone hydrazone as a toxicant, a fatty acid, a lower alcohol, a sugar, a gellant, water, a base and a hydrocarbon propellant. The gel bait composition is an oil-in-water emulsion of a toxicant-fatty acid mixture in a corn syrup solution. It is sufficiently fluent to be dispensed from a pressurized package and the deposited form will retain sufficient bulk to be ingested by cockroaches over a long period of time.
While various gel baits have been developed for the control of insects, especially cockroaches, there still remains a need in the art for a more effective bait form that provides food and moisture, especially when insects are most in need of food and moisture. The present invention provides hydrodynamic insect baits which function well in harsh microclimates and are different from the prior art baits and solves some of the problems associated with prior art baits.